One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10,15,14)(11,19,20,16)(12,17,21,22)(13,23,24,18)(1,2)(3,7)(4,8)(5,6)(9,11,15,20)(10,16,14,19)(12,13,21,24)(17,18,22,23)(25,26)(27,32)(28,29)(30,31)(33,38)(34,40)(35,37)(36,39)(1,3,5,4)(2,7,6,8)(10,14)(11,20)(12,21)(18,23)(26,31)(29,33)(32,39)(35,40)(9,12,15,21)(10,17,14,22)(11,13,20,24)(16,18,19,23)(25,27)(26,32)(28,37)(29,35)(30,36)(31,39)(33,40)(34,38)(1,4,5,3)(2,8,6,7)(9,13)(10,18)(11,12)(14,23)(15,24)(16,17)(19,22)(20,21)(25,28)(26,33)(27,34)(29,31)(30,38)(32,35)(36,37)(39,40)(9,14,15,10)(11,19,20,16)(12,22,21,17)(13,23,24,18)(25,29,30,33)(26,28,31,38)(27,35,36,40)(32,37,39,34)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.